FIELD OF INVENTION:
The present disclosure relates to a four-roll sugar cane crushing mill including rollers and the scrapers, which are hydraulically operated and the scrapers are arranged to form a duck beak shaped passage to control the re-absorption of sugar cane juice. More particularly, the present disclosure relates to the four-roll sugar cane crushing mill with hydraulically operated top roller and the scrapers, wherein the mill having plurality of holes in the compression zone to drain excess juice left over in the exit bagasse.

BACKGROUND OF THE INVENTION:
The shredded cane is passed into a series of compression achieved by set of mating sugar mill rollers. The highly compressed bagasse coming out from mill after compression in between the mill rollers has a general tendency to expand and to re-absorb the juice as soon as it expands. The high moisture reduces the mill performance drastically. High moisture is related with sugar loss and requires extra fuel in boiler to generate heat. High moisture reduces the sugar mill and boiler efficiency.
Conventionally, arrangements for limiting the moisture at mill outlet are employed in 2-roller mill with fixed type top roller. The top roller in these mills is fixed and therefore not efficient to take care of fluctuations in cane bed thickness.

US 7314191 B2 relates to “two roll sugarcane crushing mill” and provides a two roll sugarcane crushing mill which has two roll mill modules in tandem, each has a pair of main crushing rolls having a bottom roll and a top roll. The bottom and top rolls are rotatingly mounted in a pair of main frames and a pair of top beams at the two ends respectively. One end of each of the top beams is pivotally attached near an upper end of the main frames towards a feed side for swinging the top beams along with the top roll. At least one feeder roller is provided with a scraper-cum-deflector with a juice drainer in the close proximity of the main crushing rolls. The feeder rollers are mounted on an auxiliary frame which is mounted on the main frame to adjust the loading the feeder roller in a desired position. However, this prior document does not provide solution to prevent escaping of the extracted juice back into outlet bagasse. Moreover, a number of attachments have been used for the working of the mill, which make the arrangement of the mill complex.

US3969802 relates to “mill roll” of the type used for the grinding and juice extraction of sugar cane and has a plurality of peripheral grooves formed circumferentially therein with a number of holes extending radially from the bottom of these grooves into interior channels through which drainage of a further portion of the extracted juice is effected during milling. Although, the number of holes to drain excess juice have been disclosed, however, this prior art document does not provide solution to prevent escaping of the extracted juice back into outlet bagasse.

US 5273512 A relates to a mill feeder roll used in combination with another roll for force-feeding a mill of the type generally employed for grinding a material such as sugar cane and the like while contributing in pre-extracting and draining juice therefrom includes a fabricated hollow shell body mounted on a shaft with a drainage system in the form of a plurality of manifolds provided within the shell body and through which is drained a portion of the pre-extracted juice thereby leaving a drier material to be force-fed into the mill by the rotating action of the rolls. Although, this prior art document focuses on drainage of the excess juice to avoid the re-absorption during passage of the cane blanket between rolls, however, this document does not provide solution to prevent escaping of the extracted juice back into outlet bagasse.

The four-roll sugar cane crushing mill suffer from re-absorption of moisture at the mill outlet. The compressed cane while leaving the mill expands and in the process reabsorbs the juice. This increases the moisture of the cane at mill outlet. The increased moisture content degrades the mill performance. Therefore, every sugar mill is required to be designed to keep outlet moisture at minimum.

OBJECT OF THE INVENTION:

An object of the present disclosure is to provide a four-roll sugar cane crushing mill with improved mill performance.

Another object of the present disclosure is to control the re-absorption of sugar cane juice and minimize the moisture level of the outgoing bagasse from the mill and reduce losses in term of energy and sugar.

Another object of the present disclosure is to provide a four-roll sugar cane crushing mill with an arrangement to drain excess juice left over in the exit bagasse.

SUMMARY OF THE INVENTION:
An aspect of the present disclosure is to provide a four-roll sugar cane crushing mill comprising:
a top roller, a discharge roller and a pair of trailing rollers, the top roller being rotatably mounted in a bearing housing, configured to slide in a guide way according to variation in sugarcane feed; a top scraper positioned with an end proximal to the top roller; an end of a discharge scraper positioned proximal to the discharge roller disposed below the top roller, the end of the discharge scraper being mounted on a bracket hinged on a headstock and other end of the discharge scraper being mounted on fixed bolts; characterized in that the top scraper and the discharge scraper are positioned to form a duck beak shaped passage for the compressed bagasse to control the re-absorption of sugar cane juice and moisture of the exiting bagasse, the top scraper is arranged on a bracket plate configured to move with the top roller, the discharge scraper having a plurality of holes in the compression zone for draining the juice left over in the exiting bagasse and in that a pair of hydraulic cylinders are mounted on the headstock, the cylinder rods of the hydraulic cylinders being hinged with a swing plate to provide a compression force on bagasse exiting the sugar cane crushing mill.

An embodiment of the present disclosure is to provide the swing plate pressurized by the hydraulic cylinder.

Another embodiment of the present disclosure is to provide the hydraulic cylinder pressurized from back and generally kept at complete stroke out position.

Another embodiment of the present disclosure is to provide the swing plate pressurized by a turn buckle type arrangement.

Yet another embodiment of the present disclosure is to provide the top scraper and the bottom scraper are equipped with wear compensator arrangement.

Yet another embodiment of the present disclosure is to provide the hydraulic cylinder has a cylinder rod, which is retracted or in stroke out position to apply uniform pressure on the bagasse.

Still another embodiment of the present disclosure is to provide the gap between the top scraper and the discharge scraper is determined based on the thickness of the bagasse passing between the mill roller pairs.

Still another embodiment of the present disclosure is to provide the top scraper is clamped on the bracket plate which is hinged on the top roller bearing housing.

Still another embodiment of the present disclosure is to provide the hydraulic cylinders is mounted on a bracket which is further mounted on a pedestal type bracket.

These and other features, aspects, and advantages of the present subject matter will become better understood with reference to the following description. This summary is provided to introduce a selection of concepts in a simplified form. This summary is not intended to identify key features or essential features of the subject matter, nor is it intended to be used to limit the scope of the subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS:

The above and other objects and features of the present invention will become apparent from the following description of the invention, when taken in conjugation with the accompanying drawings, which respectively show:

Figure 1 shows various parts of the scrapers arrangement forming duck beak shaped passage.
Figure 2 shows four-roll sugar cane crushing mill with duck beak scraper arrangement.
Figure 3 shows conventional four-roll sugar cane crushing mill with conventional scrapers arrangement.
Figure 4 shows perspective view of the duck beak type arrangement mounted on a four-roll sugar cane crushing mill.
Figure 5 shows mounting of top scraper on top roller bearing housing.
Figure 6 shows details of the holes on discharge scraper for juice drainage.
Figures 7a & 7b show the swing plate movement as per the cane bed thickness fluctuation.

DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO DRAWINGS:

The present disclosure provides a four-roll sugar cane crushing mill with hydraulically operated duck beak scrapers, which include bottom scraper arrangement, the mounting arrangement of hydraulic cylinder (7) for duck beak type top scraper and floating provision of top scraper (4) combined together with swing plate (6). The arrangement facilitates limiting of outlet moisture of bagasse in four-roll sugar cane crushing mill with hydraulically pressurized movable top roller. The hydraulically pressurized top roller has the flexibility to slide in guide ways to take care of fluctuations in incoming prepared cane thickness. In the sugar mill of the present disclosure, the distance between bottom roller and top roller is always changing due to hydraulic cushioning provided at top roller. As an alternative of the hydraulic cylinder, a turn buckle type arrangement can be used for pressurizing the swing plate (6).

Referring to figure 1, the bagasse from the top roller (1) and discharge roller (2) is expelled from the mill by the continuous feeding of cane coming from trailing rollers. The compressed bagasse (3) is allowed to have a controlled expansion, between the top scrapers (4) and discharge scraper (5) so that it is not directly exposed to air to expand at its own. Rather it is exposed to air after passing through the narrow passage created in between the swing plate (6) and bottom scraper (5). The gap between the top scraper (4), the swing plate (6) and the discharge scraper (5) is pre-determined empirically. The swing plate (6) pressurized by predetermined hydraulic cylinder (7) force, exerts a uniform pressure on exit bagasse. The swing plate (6) is provided unique swinging action to take care of variation in cane feed. The necessary compression force in swing plate (6) is achieved by the hydraulic cylinder (7) mounted on the headstock (8), the rod (9) of the hydraulic cylinder is hinged with swing plate (6). The discharge scraper (5) acts as a fixed bed for the bagasse (3) and direct the bagasse for onwards processing. The discharge scraper (5) is provided with a no. of holes (12) (shown in figure 6) in the compression zone to help drain excess juice left over in the exit bagasse, thus minimizing the moisture of the outlet bagasse (3). The juice passed through the holes is collected at the mill bottom. The discharge scraper (5) is mounted on the bracket hinged on headstock (8). The other end of the discharge scraper (5) is mounted on fixed bolts (13) to help adjust in case of the wear of the scraper teeth (5). The top and bottom scraper are equipped with wear compensator arrangement.
The cylinder (7) is pressurized from back side and is generally kept at complete stroke out position. The stroke of the cylinder is set as per the mill setting formulas. The cylinder stroke can be varied to achieve the 2-6 times of the top roller to discharge roller opening gap to counter different mill operating parameters.
Figure 2 shows four-roll sugar cane crushing mill with scraper arranged in duck beak shape. Figure 3 shows the geometry of the top scraper (4) mounted with respect to the top roller (1) against the conventional top scraper. In the conventional scrapers the opening between the top roller scraper and discharge roller scraper is so large that it practically does not make any hindrance to the outlet bagasse and allows a free flow of the bagasse and results in reabsorption of juice back into the bagasse. Figure 4 shows perspective view of the duck beak type arrangement of scrapers mounted on a four-roll sugar cane crushing mill.

Referring figure 5 and 6, the hydraulic cylinders are mounted on bracket (14) which is further mounted on pedestal type bracket (15). In case of excess or lean bagasse (3), the cylinder (7) can retract or expand the cylinder rod (9) and a uniform pressure is always applied on the bagasse (3). The swing plate's (6) other end is hinged on headstock (8). The top scraper (4) is clamped on bracket plate (10) which is hinged on the top roller bearing housing (11) as shown in figure 5, such that it always lifts with the top roller (1) and there is no relative motion between the top scraper (4) and top roller (1), that is, when the top roller lifts, the top scraper also lifts with the roller and always remain intact with the top roller. This unique action ascertain the positive contact of top scraper (4) and top roller (1). Figures 7a & 7b show the swing plate (6) movement as per the cane bed thickness fluctuation. The swing plate acts as the final compression member putting a positive pressure on the outlet bagasse bed. The hydraulic cylinder helps to maintain the constant force on this bed. Thus, swing plate prevents the free expansion as explained above and helps to maintain a constant pressurized bed of bagasse.

ADVANTAGES:

• The moisture of the bagasse is minimized, resulting in improvement of mill performance.
• The reduced moisture saves the energy in boiler where this bagasse is burnt. The more drier the bagasse, less is the heat loss.
• The moisture is proportional to sugar loss in the bagasse, thus higher percentage of sugar is recovered from the cane.

Although the subject matter has been described in considerable detail with reference to certain preferred embodiments thereof, other embodiments are possible. As such, the scope of the disclosure should not be limited to the description of the preferred embodiment contained therein.

We claim:

1. A four-roll sugar cane crushing mill comprising:

a top roller (1), a discharge roller (2) and a pair of trailing rollers, the top roller being rotatably mounted in a bearing housing (11), configured to slide in a guide way according to variation in sugarcane feed;
a top scraper (4) positioned with an end proximal to the top roller;
an end of a discharge scraper (5) positioned proximal to the discharge roller disposed below the top roller, the end of the discharge scraper (5) being mounted on a bracket hinged on a headstock (8) and other end of the discharge scraper being mounted on fixed bolts (13);
characterized in that
the top scraper (4) and the discharge scraper (5) are positioned to form a duck beak shaped passage for the compressed bagasse (3) to control the re-absorption of sugar cane juice and moisture of the exiting bagasse, the top scraper (4) is arranged on a bracket plate (10) configured to move with the top roller, the discharge scraper (5) having a plurality of holes (12) in the compression zone for draining the juice left over in the exiting bagasse and in that a pair of hydraulic cylinders (7) are mounted on the headstock (8), the cylinder rods (9) of the hydraulic cylinders being hinged with a swing plate (6) to provide a compression force on bagasse exiting the sugar cane crushing mill.

2. The sugar cane crushing mill as claimed in claim 1, wherein the swing plate is pressurized by the hydraulic cylinder (7).

3. The sugar cane crushing mill as claimed in claim 2, wherein the hydraulic cylinder is pressurized from back and generally kept at complete stroke out position.

4. The sugar cane crushing mill as claimed in claim 1, wherein the swing plate is pressurized by a turn buckle type arrangement.

5. The sugar cane crushing mill as claimed in claim 1, wherein the top scraper and the bottom scraper are equipped with wear compensator arrangement.

6. The sugar cane crushing mill as claimed in claim 1, wherein hydraulic cylinder (7) has a cylinder rod (9), which is retracted or in stroke out position to apply uniform pressure on the bagasse.

7. The sugar cane crushing mill as claimed in claim 1, wherein the gap between the top scraper (4) and the discharge scraper (5) is determined based on the thickness of the bagasse passing between the mill roller pairs.

8. The sugar cane crushing mill as claimed in claim 1, wherein the top scraper (4) is clamped on the bracket plate (10) which is hinged on the top roller bearing housing (11).

9. The sugar cane crushing mill as claimed in claim 1, wherein the hydraulic cylinders (7) is mounted on a bracket (14) which is further mounted on a pedestal type bracket (15).